CSF

Cerebrospinal fluid is produced by the epithelial cells of the choroid plexus which are found in:

1. Inferior (temporal) horn and atrium (body) of lateral ventricle
2. Third ventricle
3. Fourth ventricle

CSF flow

It is produced at 0.4ml/min, approximately 600ml in 24 hours (active process, independent of CSF pressure).

Apart from ventricles of the brain, CSF circulates more in the subarachnoid space in the cisterns and spinal canal. 25ml of CSF is within and around spinal canal.

From the inferior horn CSF flows to body of lateral ventricles passing through interventricular foramen of Monroe to the third ventricle.

Then it goes to the fourth ventricle through aqueduct of Sylvius.

Lower part of the roof of fourth ventricle has three openings: the larger median aperture of Magendie and two lateral aperture of Luschka. CSF flows to cisterna magna through median aperture and to pontine cistern through lateral aperture.

Pontine cistern communicates with interpeduncular cistern superiorly.

The interpeduncular cistern further communicates with suprasellar cistern superiorly and ambient cistern laterally.

Suprasellar cistern extends laterally into Sylvian cistern. Optic nerve pass to the chiasm in anterior part of suprasellar cistern a.k.a chiasma cistern.

The chiasma cistern and suprasellar cistern continuous superiorly as cistern of lamina terminalis and pericallosal cistern.

This continuous posteriorly as quadrigeminal cistern.

The ambient cisterns are also continuous with quadrigeminal cistern posteriorly.

Pulsations of arteries within the cisterns play a role in CSF directional flow.

From the basal cisterns, some fluid flow down and bathes the spinal cord.

The remainder passes upward to the tentorium hiatus and diffuses over the surface of cerebral hemispheres.

CSF is absorbed through the arachnoid villi (herniation of arachnoid through holes in dura) which are numerous in superior sagital sinus.

* Pacchonian granulations (arachnoid granulations) in children that aggregates into a visible clump.

The ventricles

Lateral ventricle

- consists of four parts:

1. inferior horn (temporal horn) - extends anteriorly to the temporal lobe, may not be seen in imaging unless dilated. Its lateral wall is formed by tapetum, floor is formed by the hippocampus.
2. body (atrium) - within the parietal lobe, its medial wall formed by septum pellucidum, roof and lateral wall are formed by corpus callosum and tapetum, floor by thalamus medially and caudate nucleus laterally.
3. anterior horn (frontal horn) - extends into frontal lobe
4. posterior horn (occipital horn)- extends into occipital lobe. Often asymmetrical or present one sided usually on left side. Only 12% subjects are bilaterally well developed.

Third ventricle

- slit like, increasing size with age. Normally 2-10mm diameter.

- two recesses: supraoptic recess anteriorly (<3cm in size), suprapineal recess posteriorly.

- lamina terminalis: thin anterior wall of third ventricle between anterior commisure above to the optic chiasm below it.

Fourth ventricle

-Floor is diamond shape (rhomboid fossa), formed by posterior surface of pons and upper prt of medulla.

-Roof formed by superior cerebellar peduuncle @brachium conjunctivum with superior medullary velum in between, and inferior cerebellar peduncles @ brachium pontis with inferior medullary velum between.

-Should be symmetrical, otherwise suspect pathology

-Choroid plexus invaginates lower part of its roof.

* Fifth ventricle

-@ cavum vergae

-posterior part of foramen of Monro

-begin to close from posterior to anterior in 6 month POG, complete obliteration by 2 months of age in 85% infants.

- does not exist without cavum septum pellucidum

Aqueduct of Sylvius

-measures 15mm in length, 2mm in diameter

-passes between tegmentum (part in midbrain) and tectum (quadrigeminal plate)

-surrounded by CN III, IV and V --periaqueductal grey matter

MAMMOGRAPHY

Routine views of mammography are:

• Cranio-caudal view - to visualize inner (medial) and outer (lateral) part of the breast, part nearest to markers oftenly is the outer part.

11 criteria of a good quality image are:

1. Medial and lateral breast tissues are visualized as much as possible.


2. Aim to include pectoralis muscle.


3. Nipple is in profile.


4. No skin fold or shouder in view.


5. Symmetrical images.


6. No motion.


7. No artefacts.


8. Adequate exposure.


9. Adequate compression.


10. Proper processing.


11. Correct markers and patient's ID.

• Medial-lateral oblique view - upper and lower breast part is visualized.

11 criteria of good image quality of MLO view:

1. Pectoralis muscle should be visualized in full width.


2. Pectoral muscle viewed to nipple line.


3. Nipple in profile.


4. Inframammary fold is visualized.


5. No skin folds.


6. Symmetrical images.


7. No artefacts.


8. No motion.


9. Adequate exposure.


10. Proper processing.


11. Correct markers and patient's ID.

Images may be assessed by Computer assisted diagnosis (CAD) where the computer will mark possible area of mass, microcalcification and macrocalcifications.

Microcalcifications is defined as calcifications less then 0.5mm. Commonly reported as clusters / scatter calcifications.

Complimentary ultrasound shoud be done to:

• patient who is first time doing mammography


• suspected breast lesions to confirm nature and positions


• post mastectomy scars to look for any lesions at the scar region